The present invention relates generally to imaging, and more particularly to method and apparatus for forming multiple images.
Image analysis systems that characterize three-dimensional objects based on information from one or more two-dimensional images are used for a variety of applications. For biometric applications, such as facial recognition and fingerprint analysis, depth information is important. To acquire depth information, various methods have been deployed. In one method, images are taken with one or more cameras positioned at multiple angles and distances with respect to the object. In a second method, images are taken with a camera at multiple focus settings. In a third method, images are taken with a camera as the object is obliquely illuminated by a light source positioned at multiple angles and distances with respect to the object.
Information from multiple images can be fused to generate one or more characteristic two-dimensional composite images that contain more information than a single two-dimensional image. Imaging systems that take a series of images over an interval of time, however, are susceptible to image registration errors caused by movement of the object. Movement can be unintentional (for example, when the object is a human face, a person typically cannot hold his head perfectly still) or intentional (for example, if a facial recognition system is tracking the identities of people as they walk through an airport). Imaging systems using multiple cameras or multiple oblique lighting sources, furthermore, require multiple mounts, such as tripods, distributed about the object. What is needed is an imaging system that can take multiple simultaneous images providing depth information and other optical information. An imaging system that can be implemented as a compact, integrated, portable unit (similar to a single camera), would be advantageous.